LMAO!!! What kind of snake was it? If it's only a foot long, it may not come out for a mouse. If it's a garter snake or something, it would be more likely to eat crickets.
Snakes don't have ears, so bumping won't hurt it. It will definitely feel the vibrations, but you won't kill it that way, and it definitely won't drive it out of its hiding place.
How cold is it where you are? The snake will shut down completely, and even die, if it can't stay warm. You can use that to your advantage. If you haven't run your engine in a while, try this:
Get an extension cord and plug in a small heating blanket. Put the heating blanket inside of a shoebox, and secure the lid. Cut a 1" hole in the side of the shoebox, and put the contraption down in your floorboard. If that snake is in your car, and it's cold out, it will go straight to the warmth. You may need to leave it overnight. If that doesn't work, assuming there are no more warm spots in your car, then you can rest assured that the snake is either gone or dead.
Good luck! I'm not afraid of snakes (I have a Burmese python as a pet), but I am deathly afraid of spiders. If someone put a turantula in my ride, there would be he11 to pay.